Photographic print-out paper and prints made therefrom



Patented Apr. 27, 1926.

JAMES ADDISON JOHNSON, OF BUFFALO, NEW YORK.

PHOTOGRAPHIC' PRINT-OUT IE APER AND PRINTS MADE THEREFROM.

No Drawing.

To all whom. it may concern.

lie it known that 1, James A. JOHNSON, a citizen of the United States. residing at Bull'alo. in the county of Erie, State of New York. have invented certain new and useful Improvements in Photographic Print-Out. Paper and Prints Made There-- from: and I do hereby declare tne following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to a new photographic print-out paper and to prints or images made therefrom; and it includes the new print-out paper itself and the new prints made therefrom, as well as the methods of their production.

The new print-out paper of the present invention will print a visible image from a negative with an ordinary incandescent lamp, in a short period of time, the paper being several hundred times faster than the ordinary types of print-out paper. The visible'image produced can be made permanent by a simple treatment. The new printout paper is therefore well adapted for use where a high speed print-out paper is desired for printing a visible image. The nature and advantages of the invention will more fully appear from the following more detailed description.

The ordinary photographic paper, plate or film,- is coated with a silver bromide or silver chloride emulsion. Upon exposure to light, an invisible image is formed by the action-of the light upon the emulsion, and this invisible image is made visible by development, the developer acting upon the silver compounds that have been affected by the light. The print is then placed in a solution of sodium thiosulphate, which dissolves-away the unchanged silver bromide or silver chloride, but does not change the developed image. The use of bromide and bromochloride emulsions, therefore, involves the production of a latent image, and requires the use of a developer to develop the latent image. A visible image is produced with such emulsions only by prolonged exposure. Both silver bromide and silver chloride emulsions are light-sensitive, and willbe darkened upon eiposure to light.

Silver iodide is not turned black or dis colored on exposure to light, and ordinary silver iodide emulsions are not sensitive to Application filed April 25, 1921-. Serial No. 464,388.

light, and will not forma visible image on exposure to light. Accordingly, it has not heretofore been considered possible, so far as I am aware, toutilize a silver iodide emulsion -in photography, although small amounts of iodides have been added to chloride and bromide emulsions to somewhat increase their speed and the cleanness of working. 1

The present invention is based upon the discovery that silver iodide emulsions can be rendered sensitive to light by the action of I certain sensitizers; that the resulting sensitized emulsion has a degree of light sensitiveness which adapts it to particular advantage for use in printing visible images; and that the resulting images or prints can be desensitized. without removing the unchanged silver iodide from the emulsion.

The new print-out paper is made by producing and sensitizing a silver iodide emulsion. Before sensitizing, the silver iodide is not light-sensitive, but it becomes light-sensitive after it has been subjected to the action of the sensitizingsolution and subsequently dried. The sensitized silver iodide emulsion can be. made by different methods.

One preferred method of making the new print-out paper is to make use of previously prepared silver chloride or silver bromide emulsion papers and to treat these papers with a sqlut-ion of a soluble iodide, such as sodium, potassium, or ammonium iodide. This results in the conversion of the emulsion into a silver iodide emulsion which is 7 produced, either before or after drying, is

then treated with a solution of a sensitizer, and then dried. The silver iodide emulsion itself is not light-sensitive, nor does it become light-sensitive when treated with a solution of the. sensitizer, but it becomes lightsensitive after such treatment and after the treated emulsion has been dried, so that the dried product is light-sensitive.

The paper which is treated may thus be a bromide, chloride or bromochloride coated paper, or, instead of a paper, a plate or film can be similarly treated. The paper (or the late or film) may be treated, for examp e, by soaking it a few minutes in a 1% to 5% solution of potassiumiodide, or-the paper, if.-in-.rolls,'-- can-bepassed through such a solution at a regulated rate to give it the desired treatment. After this treatment, the paper is washed in Water and then soaked or treated for from 5 to 10 minutes in a suitable sensitizing solution, e. g., a solution containing monomethyl paramidophenol sulfate and sodium suliite in amounts equal to about a 2% solution of monomethyl paramidophenol sulfate and an 8% solution of sodium sulfite. After the soaking in the sensitizing solution, the paper, film or plate, is then dried in the dark.

The sensitizing solution can be made, for example, by adding the monomethyl paramidophenol sulfate to water to form about a 2% solution, and then adding the sodium sulfite to give about an 8% solution. That is, the monomethyl paramidophenol sulfate may be almost a saturated solution, and the sultite then added until the solution becomes as saturated as possible Without bringing about the formation of a precipitate.

It is one advantage of the method above described that it enables ordinary bromide, chloride or bromochloride papers, films or plates, to be used, thus avoiding the necessity for producing the emulsion 1n the first instance, and the coating of the paper or other support therewith. Thus, paper which has thus been condemned for its intended purposes, because of the lapse of time, and which would ordinarily be destroyed to recover the silver content of the emulsions, can advantageously be utilized in producing the new print-out paper of the present invention.

Silver chloride and silver bromide papers are now manufactured of greatly varying speed; and the,speed of the print-out paper of the present invention will correspondingly vary to a greater or less extent.

Another method of producing the new paper of the present invention is by making an emulsion of silver iodide in gelatin, in

much the same manner that silver chloride" and silver bromide emulsions are now made, using care to have the silver and iodine atomieally balanced, that is, in proportions to form silver iodide without any excess of either the silver or the iodine. After thorough washing, the silver iodide emulsion is used to coat the paper or other support. When the emulsion is set and dry, it is soaked in a sensitizing solution, such as that above described, and then dried in the dark to give the sensitive paper or film. etc.

The silver iodide emulsion can also be treated with a sensitizing solution before the emulsion is applied to the paper or other support.

The method of producing the new printout paper has the advantage that it can be carried out in Hthe daylight, inasmuch as the silver iodide emulsion itself is not seasitive to light, nor is the emulsion after it is treated with the solution of the sensitizer and before drying, but the product becomes light-sensitive only when dried. When, however, a light-sensitive chloride or bromide emulsion, 01' paper coated with it, is utilized as the starting material of the process, it should, of course, be rotected from theaction of the light until it has been converted to an iodide emulsion.

While I have described the process more particularly in connection with the production of a print-out paper coated with the light-sensitive silver iodide emulsion, yet it will be understood that films or plates or other supports can be similarly coated. For simplicity of description, instead of referring to films, plates, papers, etc., I will refer, in the following description of the inventionfmerely to a paper, and to prints made therefrom.

The new print-out paper, as will be seen from the above description, is a sensitized silver iodide paper, having a light-sensitive silver iodide emulsion. By thus referring to the paper as a silver iodide paper, and the emulsion as a silver iodide emulsion, I do not wish to be understood as meaning that the silver iodide is necessarily present as such in the emulsion as the silver and iodine may be present, to a greater or less extent, in a complex -state of combination with the gelatin or other constituents of the emulemulsion, but other emulsions, such as a collodion emulsion, can be similarly used, and with similar advantages, for example, a silver iodide collodion emulsion can be made and applied to the paper, and the coated paper then treated with the sensitizing solution and subsequently dried .to give the light-sensitive coated paper.

Difi'erent sensit-izers can be used for converting the light-insensitive silver iodide emulsion into a light-sensitive emulsion. The sensitizers which Ihave found particularly advantageous are n'ionomcthylparaamidophenol sulfate, aminosali-genineacetone sulfite, paraamidophenol sulfate, although I have found other sensitizers to give good results, including paradihydroxybenzole, orthodihydroxybenzole. paradihydroxybenzole, hydrochloride, and sodium amidobetanaptholbeta sul-fonate. Equivalents of these materials will appear to one skilled in. the art. The aetion'of these sensitizers is materially improved by the addi ion of a sulfit such as sodium or ence of both a sulfite and an alkali. For use as sensitizers, they should be used without an alkali.

The sensitizing operation, for making the silver iodide emulsion light-sensitive, involves merely the treating of the silver iodide emulsion with a solution of the sensitizer, usually with the addition of a sulfite which increases the sensitizing effect and appears to be advantageous in preserving the emulsion. After the emulsion is treated with a solution of the sensitizer, it should be dried without washing, so that the sensitizer is not removed. The sensitizing action does not appear to be completed until the emulsion is dried, as, before drying, the emulsion is not light sensitive, but becomes so on drymg.

The print-out paper produced as above described is particularly advantageous for use as a print-out paper because of its greatly increased speed, and because it makes possible the printing of visible images from negatives with an ordinary incandescent light. The printing operation does not require the use of adark room, but can be carried out in an ordinary dimly lighted room. For example, I have obtained a good image upon the paper by exposing thepaper under an ordinary negative at a distance of eight inches from a 300 Watt light, in from fifteen to ninety seconds, although the speed of the paper can be varied considerably, and papers of increased or decreased speed produced.

It is a characteristic advantage of the new print-out paper thatit prints a, visible image whichrequires no subsequent development, and that such a visible image can readily be obtained upon exposure to sources of light such as an incandescent electric light which cannot be used with ordinary photographic print-out papers.

When the visible image has been formed by exposure until the prints look about as the final result is desired to be, the further action of light upon the prints can be prevented by subjecting them to a washing operation to wash out and remove the sensitizer. Bv thus desensitizing the prints the image will be left with substantially the same appearance as that produced by the printing operation, and it is not necessary to remove the unchanged portions of the silver iodide from the emulsion, as these are no longer light sensitive.

It'is advantageous, however, in order to give an increased permanence to the prints,

to subject them to the action of a dilute somewhat intensifies the print and seems to improve the permanence of the image. The prints may thus be washed in running water at about for a period of about 20 minutes and'then soaked for a few minutes in a dilute alkali solution, for example, in a sodium hydrate solution for about "10 minutes, then washed for a further period of, for example, 10 minutes, and then dried.

It will thus be seen that the print-out paper can be used in a simple and advantageous manner, merely by exposure until the image has been produced, and then by a simple washing operation to remove the sensitizer and desensitize the print and thus prevent further change in the emulsion.

The print thus produced, accordingly, contains the unchanged silver iodide, as well as that which has been changed by the action of the light into the visible image; and the presence of the unchanged silver iodide is a characteristic of the prints or images produced in accordance with the present invention. In referring to the silver'iodide as remaining in part unchanged in the finished print, after the visible image has been produced and made permanent, I do notdesire to be understood as meaning necessarily that no change has taken place in the silver iodide, but that the silver iodide remains on the final print or image in a desensitized state such that it does not require, to'be removed from the finished print, and such that it does not interfere with the production of the desired permanent image. but gives to the final print a somewhat different appearance from ordinary prints, and that the portions of an ordinary print which appear white on white paper, or appear transparent on a film or plate, have the appearance of theunchanged silver iodide emulsion in the finished prints of the present invention.

The new prints, as above described, therefore diife-r radically from ordinary prints, which are produced by development of an invisible image, and with subsequent removal of the portions of the emulsion which are unacted upon by the light. If the finished prints, produced as above described, are treated with sodium thiosulfate, not only the nnacted upon portions of the emulsion, but also the image itself, isdissolved and disappears. The image, therefore, is of a radically difierent character from the images produced by development of ordinary prints, in which the images are unacted upon by sodium thiosulfate solutions.

Another method of using the new printout paper and of producing images therefrom,=is tooarry' the printing operation only part way until the high lights are slightly rinted and then to place the prints in a dilute solution of an alkali, for example, a 10% sodium carbonate solution for 10 minutes or more, then to wash the print and to dry it; The alkali bath is somewhat improved by adding sodium sulfite to it, for example, a 10% solution. When the print is treated in this way and is added directly to'the alkali solution before the sensitizer is removed by washing, the partly developed image is completely developed, without any apparent change taking place in the portions of the silver iodide emulsion which lave not been acted upon by the light. The

- treatment with alkali and the subsequent washing operation removes the sensitizer-s so that the final print is no longer. sensitive to light, although it still contains silver iodide which has apparently not been acted upon, and which is present in a form insens1tive \o light.

The print or image produced in this way dill'crs from the print or image produced as above described, 'in that, upon treatment with sodium thiosulfate, the image is not removed, although the other portions of the silver iodide are dissolved away.

The color of the print produced will vary somewhat with the method of treatment. If no alkali is used, and if the print is desensitized by washing out the sensitizer, the prints will usually have a brown tone, although this will depend somewhat upon the character of the emulsion originally used. Treatment with alkali tends to change the brown tones to bluish tones. The unchanged portions of the silver iodide emulsion are of a light yellowish color, and are translucent.

The print-out paper of the present invention is well adapted for use in amateur photography, as it enables a rint to be made by ordinary artificial lig t without the use of a dar: room and with the production of avisible image, while it also avoids the necessity for the usual developing and fixing operations. A simple desencitizing treatment is all that is required after the printing operation, which may be efl'ected by washing alone or by washing and subsequent treatment with alkali, or by direct treatment with an alkaline solution of a partly printed image.

The new print-out paper is also of particular advantage. for use in conjunction with a radium encil, in self-recording meters and other evices, the radium penc1l acting as the source of light and making a permanent record upon the paper.

The pa ier, moreover, has certain ecuiarities 0 its ownwhich further di erentiate it from ordinary photo a hic papers. It is sensitive to heat, and w l an e color somewhat wheaheatedgo taco r can be somewhat varied by a regulated heating operation.

B incompletely removing the sensitizer, whi e removing the greater portion of it, the image or print produced canb'e 'made of a temporary character, such that it will darken after a short time if exposed to light; or an image can be produced which will fade out in a short time, thus makin the paper available for use 1n proofs and for other purposes where a temporary print is desired.

' The prints made from the new rint-out paper, in the manner above descri ed, can'- not be copied on the ordinary wet plate used by photo engravers, for the reason that it will reflect no extreme violet or ultra-violet light. The paper is quite sensitive to the rod end of the spectrum, even the infra red,-- features which further serve to differentiate it from ordinary hotographic pa er. The sensitiveness of tie paper to light waves of different lengths can be increased or decreased by the addition to the emulsion of suitable compounds, e. g., sensitizing dyes.

I have further found that certain prints made according to the present invention, and which had faded after exposure to light, were nevertheless still capable of development by the action of a regular photographic developer, such as monomethyl paramidophenol sulfate, sodium sulfite and sodium carbonate. The faded rints were brought back to about their original value, indicating that the parts of the print that contained the original image, even when 'aded out by the sun until they were not visible, could nevertheless be brought back by ordinary photographic development. When, however, regular prints which have not been faded, are subjected to the action of a photographic developer, they become overdoveloped and very much darker than the original image.

While I do not desire to limit myself by any theoretical explanation of the action which appears to take place, when the ima e is formedby the action of light upon the silver iodide emulsion, this action can perhaps be explained by assuming that the silver iodide, or the complex organic compounds of silver and iodide. contained in the emulsion, are changed by the action of the light to a silver subiodide or to some other visible silver compound, and that some of the iodine is taken up by the sensitizer and is removed therewith from the .finished print when it is desensitized. Whatever the theoretical explanation of the action may be, this action is nevertheless of such a' character that the silver iodide emulsion is chan ed and animage produced, which may be sit or completely visible, or partly visible and subsequently developed. I

It wil thus be seen that thepresent ill-' the treated emulsion to complete the Sens1tiz-' ing operation.

- The print-out paper (or the film, plate, or other base'coated with the emulsion) can then be directly used for making prints or images, in a simple and advantageous manner and according to different methods of procedure, and with the production of prints having certain properties in common, but which may difi'er from each other in differ ent respects. The print may thus be formed by printing the image to full strength and then washing the paper in plain water to remove the sensitizer. For increasing thepermanence of the print, it may be treated, after washing to remove the sensitizer, with a dilute alkali solution, such as a solution of sodium hydrate or potassium hydrate, ammonia, sodium carbonate, etc. A print of a somewhat diiierent character can be obtained by printing only far enough so that the details show a little in the high lights,

and by then placing the print in a solution of an alkali to develop the image completely, and by then washing the print and drying it.

In referring to the print-out paper in the accompanying claims, as a paper, I intend to include as equivalents, films, plates, etc.,

- similarly coated with the light-sensitive silver iodide emulsion. So also, in referring to to emulsion, in the accompanying claims, as a silver iodide emulsion, or as a light-sensitive silver iodide emulsion, I intend thereby to define the emulsions such as are produced in the manner above described.

I claim:

1. The method of producing a light-sensitive photographic emulsion, which comprises treating an emulsion of a silver compound other than silver iodide with a water-soluble iodide to form a silver iodide-emulsion, and treating the resulting emulsion with a sensitizer to render the silver iodide light sensitive.

2. The method of producing light-sensitive silver iodide emulsions, which comprises forming the emulsion in the presence of an excess of the iodide radical over that required to combine with the silver present and thereafter treating the emulsion while still containing an excess of the iodide radical with a sensitizer capable of rendering silver iodide sensitive to light in the absence of water-soluble silver salts and without development.

3. A li ht-sensitive emulsion free from water-solu le silver salts and containing silver iodidemnd a sensitizer, said sensitizer being capable of sensitizing silver iodide so that it will darken on ex osure to light in the absence of water-solub e silver salts.

4. A light-sensitive emulsion free from water-soluble silver salts and containing silver iodide and a sensitizer, said sensitizer being capable of sensitizing silver iodide so that it will darken on exposure to light in the absence of water-soluble silver salts,

said emulsion being capable of being desensitizedwithout the removal of silver iodide therefrom.

5. A light-sensitive emulsion free from water-soluble silver salts and containing silver iodide, a water-soluble iodide and a sens tizer, said sensitizer being capable of sensitizing silver iodide so that it will darken on exposure to light in the absence of watersoluble silver salts.

6. A light-sensitive emulsion free from watensoluble silver salts and containing silver iodlde, an organic sensitizer and an inorganic. accelerator, said sensitizer being capable of sensitizing silver iodide so that it will darken on exposure to light in the absence of water-soluble silver salts.

7. A light sensitive silver iodide emul- S1011 containing a water soluble iodide, an organic sensitizer, and an inorganic accelerator. r l

8. 'ljhe' method of producing a photographic prmt-out paper, which comprises treating with a water-soluble iodide a paper containing a silver salt the acid radical of which is replaceable by the iodine of the said iodide to form silver iodide, treating the resulting paper with a solution of a sensitizer, and then drying the paper.

photographic print-out paper, comprising a support having an emulsion thereon free from water-soluble silver salts and containing silver iodide and a sensitizer, said sensitizer being capable of sensitizing silver iodide so that it will darken on exposure to light in the absencc of water-soluble silver salts, and said paper being capable of printing an image directly on exposureto lighton free from water-soluble silver salts and containin silver iodide, a water-soluble iodide an a sensitizer, said sensitizer being capable of sensitizing silver iodide so that it will darken on exposure to light in the absence of water soluble silver salts, and said-fpalper being capable of printing an image irectly on exposure to light without development.

' 12. A photogra hic print-out aper, comprising a support raving an emu S1011 there- -on free from water-soluble silver salts and containing silver iodide, an organic sensitizer and an inorganic accelerator, said sensitizer being capable of sensitizing silver iodide so that it will darken on exposure to light in the absence of water soluble silver salts, and said paper being capable of rintin an image directly on exposure to ight without development. 13. A support sensltized with silver iodide rendered light sensitive in the absence of water-soluble silver salts and in the presence of water-soluble iodides by a sensitizer capable of sensitizing silver iodide so that it will darken on exposure to light in the absence of water-soluble silver salts, said sensitized support being capable of formin directly an image on exposure to light'wit iout deve opment.

14. The method of producing a print or image upon a light-sensitive silver iodide emulsion, which comprises exposing the print until the image is visible, and desensitizing the print without removmg the unchanged silver iodide from the emulsion.

15. The method of producing a printer image upon a light-sensitive silver iodide emulsion, whichv comprises exposing the print until the image is visible, and desensitizing the print by washing with water.

16. The method of producing a print or ima e upon light-sensitive silver iodide" emu sion which comprises exposing the print until the image is visible, desensitizmgsthe print by washing with water and su equently treating wit an alkaline solunon.

17. The method of producing a print .or ima e upon a light-sensitive silver iodide emu sion, which comprises exposing the print, and then treating the print with a ilute alkaline solution to develop the image.

18. The method of producinga print or image from a light-sensitive silver iodide emulsion, which comprises exposing the print until the image is visible, andafterwards de-sensitizin the print.

19. A photograp iic print or image made by the action of light upon an emulsion free from water-soluble silver salts and containing a water-soluble iodide and light-sensitive silver iodide without development, said print or image being insensitive to light, the emulsion containing light-insensitive silver iodide.

20. A photographic print or image made by the action of light upon an emulsion free from water-soluble silver salts and containing silver iodide, a water-soluble iodide and a sensitizer capable of rendering the silver iodide sensitive to light in the absence of water-soluble silver salts without development.

21. A photographic print or image made by the action of light upon light-sensitive silver iodide, said print or image being desensitized and still containing silver iodide but in a light-insensitive condition.

In testimony whereof I afiix my signature.

. JAMES ADDISON JOHNSON. 

